Ramp calculator
Choose the kind of ramp and what to work out: the gradient from the rise and length, the length of run a rise needs, or the rise a run reaches. Enter the levels as a rise or as the RLs on the drawings, and the gradient as 1 in N, a percentage or degrees. The calculator says whether it is a ramp or a walkway under AS 1428.1:2021 and checks the landings, handrails, width and crossfall for that kind.
What it checks
The same engine as the calculator in AEC Assistant, with every table checked against NCC 2025 or the Standard it calls up. The same inputs always give the same result.
Background: Ramp requirements guide
You enter
- Ramp kind: pedestrian ramp or walkway, step ramp, threshold ramp, kerb ramp, driveway
- What to work out: the gradient, the length of run or the rise
- Levels as a rise in millimetres, or as the bottom and top RLs in metres
- Length of run and clear width in millimetres; a gradient as 1 in N, a percentage or degrees
- Crossfall
It reads from
- AS 1428.1:2021 clauses 7.2 to 7.7, 3.3 and Section 9
- NCC 2025 Volume One D3D11(3), Table D3D15, D3D22(2)(a)(ii) and D4D12
- AS/NZS 2890.1:2004 clauses 2.5.3 and 2.6.2 for a driveway
A worked example
The calculator's example inputs, checked.
Gradient
1:14.0
Ramp (1:14 to steeper than 1:20) · 7.1% · 4.1°
Complies with AS 1428.1:2021 Cl 7.3 on the figures entered. The requirements marked for checking still apply on site.
- Gradient1 : (length ÷ rise) = 1 : (4200 ÷ 300) = 1:14.0 · 7.1% · 4.1°AS 1428.1:2021 Cl 7.3
- Landing interval (max ramp run before a landing)4200 mm · limit ≤ 9000 mmAS 1428.1:2021 Cl 7.3(c)
- Clear width1000 mm · limit ≥ 1000 mmAS 1428.1:2021 Cl 3.3
- Total rise in a series of connected ramps300 mm (this run) · limit ≤ 3600 mmNCC 2025 Vol One D4D12(a)
Questions
What gradient can an accessible ramp be?
Under AS 1428.1:2021 a ramp is steeper than 1:20 and not steeper than 1:14 (clause 7.3); a walkway is 1:20 or flatter. A step ramp may be up to 1:10 over a rise of not more than 190 mm (clause 7.6), and a kerb ramp or threshold ramp up to 1:8 (clauses 7.7 and 7.5). The calculator tells you which one your rise and length make.
How long does a ramp need to be?
The length of run is the rise times N for a gradient of 1:N. At 1:14, the steepest a ramp may be under AS 1428.1:2021 clause 7.3(a), a 300 mm rise needs 4.2 m of run; at 1:20 it needs 6 m. Choose Length of run, enter the rise or the two RLs off the drawings, and the calculator works out the run and checks the landings it needs.
How often does a ramp need a landing?
AS 1428.1:2021 sets the maximum length between landings by gradient: 9 m at 1:14 (clause 7.3(c)), longer as the ramp flattens and 15 m or more on a walkway (clause 7.2(b)). The calculator shows the interval for the gradient you enter.
Does the ramp calculator cover handrails?
Yes. A ramp steeper than 1:20 needs a handrail on each side (clause 7.3(e)), 865 to 1000 mm high (clause 9(d)) and extending 300 mm past the top and bottom (clause 7.3(i)), with the 1000 mm clear width of an accessible path (clause 3.3). A step ramp, threshold ramp or kerb ramp needs no handrail: NCC 2025 Volume One D3D22(2)(a)(ii) excludes them.
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Ask about the ramps on your own project
The free plan answers from the National Construction Code, state building and planning legislation, ABCB handbooks, regulator practice notes and codes of practice, with the clause cited. Plus adds the Standards, including AS 1428.1:2021, from A$79 a month plus GST.